Thoracic injuries caused by blunt trauma are commonly encountered emergencies in veterinary medicine. However, no literature exists comparing radiography to computed tomography (CT) in blunt thoracic trauma caused by motor vehicle accidents in canine patients. The aim of this prospective case series was to estimate the sensitivity (Se) and specificity (Sp) of thoracic radiography relative to CT for detecting lung contusions, pneumothorax, pleural effusion and rib fractures. The study further aimed to establish a severity scoring system for radiography and CT and to compare the findings between the two modalities. The hypothesis was that radiography would be less sensitive than CT at detecting these injuries and that radiography would underestimate the severity of lung contusions compared to CT. Fifty-nine patients met the inclusion criteria. Radiography underestimated the presence of lung contusions (Se = 69%, 95% Confidence interval (CI)) and overestimated the severity of the contusions relative to CT. There was also high interobserver variability in evaluating lung contusion severity (coefficient of variation = 91%). Both the three-view thoracic and horizontal beam radiography had poor sensitivities for the detection of pneumothorax (Se = 19% and 63% respectively) and pleural effusions (Se = 43% and 71% respectively). Similarly, the sensitivity (56%) of three-view thoracic radiographs for the detection of rib fractures was poor relative to CT. To conclude, three-view thoracic radiography had low sensitivity for pathology related to blunt thoracic trauma caused by motor vehicle accidents and CT could be considered as an additional diagnostic imaging modality in these patients. / Dissertation (MMedVet (Diagnostic Imaging))--University of Pretoria, 2019. / Companion Animal Clinical Studies / MMedVet (Diagnostic Imaging) / Unrestricted